Climate effects of a “minor” nuclear war

Nuclear Famine, Independent Australia  17 April 2016Daryl Williams discusses a recent scientific report in which the devastating global impacts of a small nuclear conflict, including “nuclear famine”, are outlined.

THE COLD WAR is over, the Berlin Wall has fallen, nuclear warhead numbers have declined significantly — so the threat of nuclear catastrophe has passed, right?

Well, sadly no.

In fact, things may be more dangerous today than at the height of the Cold War.

Computer simulations of the indirect climate effects of even a “small” regional nuclear exchange indicate that the whole world would still be imperiled.

A recent 16-page scientific paper, ‘Multidecadal global cooling and unprecedented ozone loss following a ‘regional nuclear conflict‘, by MillsToonLee-Taylor and Robock, outlines the horrific unexpected consequences. Once you boil down the “science-speak” it paints a bleak picture – via an “Earth system model” which includes atmospheric chemistry, ocean dynamics and interactive sea ice and land components – which we should do everything we can to avoid.

It deserves far more attention than it has received and its findings should be informing our foreign, defence and emergency management policies. In summary, the scenario it simulates is as follows:

Firestorms in India and Pakistan from a “small” regional conflict and nuclear exchange would inject 5 Tg (or one million tonnes) of black carbon (smoke, soot, dust) into the stratosphere which spreads globally.

The black carbon heats the stratosphere (by up to an amazing 80 degrees C) and cools the lower atmosphere and surface (by 1.1 degrees C in the first four years, down to 1.6 degrees in the fifth year, slowly rising to 0.25 to 0.5 degrees 20 years later). The colder surface temperatures reduce precipitation by 6% globally for the first five years and still by 4.5% one decade on.

Oh, and hundreds of millions of Indians and Pakistanis would be incinerated to death … but let’s concentrate on the long-term climate repercussions.

The heating of the stratosphere caused by the black carbon produces a dramatic loss of ozone (30% to 45% at mid-latitudes for the first five years, 50 to 60% at northern high latitudes) giving ‘a global ozone loss on a scale never observed‘.

It is the combination of dramatic extended drops in surface temperatures termed ‘the coldest average surface temperatures in the last 1000 years’ and precipitation with a dramatic increase in UV radiation.

That spells big trouble for Earth in the form of

widespread damage to human health, agriculture, terrestrial and aquatic ecosystems.’

That is,

‘…combined cooling and enhanced UV would put significant pressures on global food supplies and could trigger global nuclear famine.’

As well, ‘… the average growing season is reduced by up to 40 days throughout the world’s agricultural zones over these five years’. The increased UV-B radiation would reduce plant height, shoot mass and foliage area, damage DNA and significantly increase insect losses. A 16% loss of ozone could reduce phytoplankton levels in the ocean by 15%, resulting in a loss of seven million tons of fish per year……..
Regional extremes can be worse. Large areas of continental landmasses would experience significantly greater cooling than average:

Winters (JJA) in southern Africa and South America would be up to 2.5 degrees C cooler on average for 5 years … [and] … most of North America, Asia, Europe and the Middle East would experience winters (DJF) that are 2.5 to 6 degrees C cooler … and summers (JJA) 1 to 4 degrees C cooler.

Which is worse than any volcanic winter in the last 1000 years. There would be significant regional drying over the Asian Monsoon region, including the Middle East, the Indian subcontinent and Southeast Asia, as well as the Amazon, the American South-East and Western Australia — which would be 20% to 60% drier.

All from a “minor” nuclear exchange  between India and Pakistan……..,8893


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